Gas delivery substrates (“GDS”) are used with delivery of gas fuel to a fuel cell. The GDS acts as a substrate onto which fuel cell components (anode, electrolyte, and cathode) films are deposited. GDS are typically formed from a ceramic material and are shaped in the form of a flat tile containing internal channels and microporous walls. The purpose of the channels is to deliver gaseous fuel to the surface of the substrate. The fuel gases permeate through the GDS to its surface, providing fuel to the anode of the fuel cell.
Known GDS are manufactured by conventional hydroplastic ceramic extrusion of oxides such as magnesium oxide doped magnesium aluminate (MMA). In this process, a ceramic powder is mixed with water based organic matrix to form a mud or dough-like material, and then extruded into a part with a desired shape. Once extruded, the mud must be dried (i.e., the water has to be removed), a slow step in the manufacturing process. Also, the dried part is relatively fragile, so secondary operations on the part are not practical. Further, the relative fragility requires that any walls made in the extruded shape are limited to a relatively large thickness. GDS made by this process are ceramic refractories that are rather large, heavy, and thick walled. It would be highly desirable to make GDS more compact and of lighter weight. Provision for sealing around the edges of a GDS should also be made easier.